From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A995C4338F for ; Wed, 4 Aug 2021 18:19:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B76560F94 for ; Wed, 4 Aug 2021 18:19:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239005AbhHDST2 (ORCPT ); Wed, 4 Aug 2021 14:19:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:52284 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230229AbhHDSTI (ORCPT ); Wed, 4 Aug 2021 14:19:08 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 490FA60F58; Wed, 4 Aug 2021 18:18:55 +0000 (UTC) Date: Wed, 4 Aug 2021 14:18:48 -0400 From: Steven Rostedt To: LKML Cc: Ingo Molnar , Andrew Morton , Daniel Bristot de Oliveira Subject: [PATCH] tracing: Quiet smp_processor_id() use in preemptable warning in hwlat Message-ID: <20210804141848.79edadc0@oasis.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" The hardware latency detector (hwlat) has a mode that it runs one thread across CPUs. The logic to move from the currently running CPU to the next one in the list does a smp_processor_id() to find where it currently is. Unfortunately, it's done with preemption enabled, and this triggers a warning for using smp_processor_id() in a preempt enabled section. As it is only using smp_processor_id() to get information on where it currently is in order to simply move it to the next CPU, it doesn't really care if it got moved in the mean time. It will simply balance out later if such a case arises. Switch smp_processor_id() to raw_smp_processor_id() to quiet that warning. Fixes: 8fa826b7344d ("trace/hwlat: Implement the mode config option") Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_hwlat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index a6c0cdaf4b87..14f46aae1981 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -327,7 +327,7 @@ static void move_to_next_cpu(void) get_online_cpus(); cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask); - next_cpu = cpumask_next(smp_processor_id(), current_mask); + next_cpu = cpumask_next(raw_smp_processor_id(), current_mask); put_online_cpus(); if (next_cpu >= nr_cpu_ids) -- 2.31.1